Soft switch type bidirectional series resonance converter and constant gain control method thereof

Abstract

The invention discloses a soft switch type bidirectional series resonance converter and a constant gain control method thereof, and belongs to the technical field of switching power sources in the field of power electronics. According to the converter disclosed by the invention, zero-voltage switch on (ZVS) of all MOS transistors (Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8) in a full-load range can be realized by virtue of the added auxiliary inductors (L1, L2), so that the switching loss of the system is lowered; and in addition, the ring current loss can be reduced under the constant gain control method, and the transmission efficiency can be effectively improved. Due to the fact that a symmetric topological structure is adopted, under the forward and reverse operation mode, the working performance of the converter is the same; and under the constant gain control method, when the energy flow direction changes, the control logic does not need to be replaced, and natural bidirectional flow of energy can be realized. According to the converter, the input and output voltage ratio is the transformer ratio directly, and the constant-voltage gain characteristic which does not change along with a load is presented.

Description

technical field [0001] The invention belongs to the technical field of switching power supplies in the field of power electronics, and in particular relates to a soft-switching bidirectional series resonant converter and a constant gain control method thereof. Background technique [0002] With the increasingly serious problems of energy depletion and environmental pollution, microgrid systems based on renewable energy have developed rapidly in recent years. The microgrid system includes a distributed power generation system composed of wind turbines, fuel cells, and photovoltaic arrays, and an energy storage system composed of lithium battery packs, power electronic interface devices, and supercapacitors. Among them, the power electronic interface device facilitates the flow and distribution of energy between the power generation system, energy storage system and load. In consideration of bidirectional power flow, voltage matching and safety issues, a bidirectional DC-DC c...

AI Technical Summary

Problems solved by technology

It is usually controlled using a variable frequency control strategy, however, this converter has the lowest impedance only at the resonance point, and the voltage gain is 1, once it is far away from the resonance point, the gain is lower than 1 and there is a large energy circulation , reducing its transmission efficiency

The primary-side fixed-frequency phase-shift control is also one of the more common control strategies. This method cannot make the voltage gain greater than 1, and at the same time, a large phase-shift angle will also cause a large loop loss.

Neither of these two methods can enable the converter to be used as a DCX, nor can it realize the natural two-way flow of energy. In addition, under the traditional bidirectional series resonant converter topology, the forward and reverse work performance is inconsistent, and the soft power under the full load range cannot be realized. switch

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